London: Scientists claim to have
found the brain impulse which makes us all quit in the end --
in fact, they have also pinpointed the precise part of the
brain which tells you when that time has arrived.
A team at Duke University says that the impulse which
told ancient foragers to give up on one pasture and move on to
more fertile hunting grounds is the same as that which urges
people to try a different internet site if our initial choice
is taking too long to appear on screen.
The scientists found that a section of the brain
called dorsal anterior cingulate cortex (ACC) is responsible
for weighing up reward against cost in any given situation.
When a certain threshold is reached, the brain gives a signal
to throw in the towel, a newspaper reported.
For their study, the scientists analysed rhesus
macaques monkeys. They observed whether the monkeys decided to
stay with a food source giving ever smaller squirts of fruit
juice or move to a newer and potentially better supply.
They studied a set of neurons within the animals`
ACCs, which showed increasing activity as time passed. Once it
reached a certain threshold the monkeys immediately moved on.
Lead scientist Prof Michael Platt said: "It is as if
there is a threshold for deciding it`s time to leave set in
The scientists also factored in the time it would take
to travel to the next food source and when this was increased,
it took longer for the "quit" threshold to be reached.
Prof Platt said that the findings tallied with a 1976
evolutionary theory, the Marginal Value Theorem, which stated
that foragers would stay longer at a blackberry bush as the
distance between bushes became greater.
The idea has been shown to hold true across the animal
kingdom in worms, bees, fish and seals. Prof Platt said: "This
is a really fundamental solution to a fundamental problem."
He said that the same was true when it came to our
use of modern technology. "In the case of internet users, the
cost of travel time translates to download speed. The faster
the downloads, the quicker browsers are willing to forage
elsewhere," he said.